Control method of energy storage system and energy storage system

Abstract

The invention provides a control method of an energy storage system and the energy storage system. The energy storage system comprises N energy storage sub-modules, N is a positive integer larger than 1, the control method of the energy storage system comprises the steps that the state parameters of each energy storage sub-module in the N energy storage sub-modules are obtained, and the state parameters comprise at least one parameter of the battery remaining capacity SOC, the battery health degree SOH, the IGBT junction temperature and the battery temperature; and according to the state parameter of each energy storage sub-module, working states of the N energy storage sub-modules are controlled, and the working states comprise an input state and a cut-out state. According to the technical scheme provided by the embodiment of the invention, the working state of the energy storage sub-module in the energy storage system can be controlled according to the plurality of state parameters, so that the utilization rate and the reliability of the system are improved.

Description

Energy storage system control method and energy storage system Technical Field

[0001] The present application relates to the field of energy storage, and in particular to a control method for an energy storage system and an energy storage system. Background Art

[0002] In order to enhance the effective power regulation capability of the Flexible DC transmission system and give full play to the role of the Flexible DC transmission system in grid regulation, the application of energy storage system in the Flexible DC transmission system has important research significance.

[0003] The energy storage system in a flexible DC transmission system primarily achieves energy storage by connecting energy storage submodules in series to form ultra-high voltage. The switching strategy of the energy storage submodules affects the utilization rate of the energy storage system.

[0004] Therefore, how to improve the utilization of the system is an urgent problem to be solved.

[0005] Summary of the Invention

[0006] The present application provides a control method and an energy storage system, which can control the working state of energy storage submodules in the energy storage system according to multiple state parameters, thereby improving the utilization and reliability of the system.

[0007] In a first aspect, a control method for an energy storage system is provided, wherein the energy storage system includes N energy storage submodules, where N is a positive integer greater than 1, and the method includes: obtaining state parameters of each of the N energy storage submodules, the state parameters including: battery remaining capacity (State of Charge, SOC), and at least one of battery health (State of Health, SOH), IGBT junction temperature, and battery temperature; and controlling the operating state of the N energy storage submodules according to the state parameters of each energy storage submodule, the operating state including an on-state and a off-state.

[0008] In an embodiment of the present application, when the status of N energy storage submodules in an energy storage system is not determined, the SOC of each of the N energy storage submodules and at least one of the SOH, IGBT junction temperature, and battery temperature are first obtained, and then the status of each energy storage submodule is controlled based on the SOC of each energy storage submodule and at least one of the SOH, IGBT junction temperature, and battery temperature. In this way, by controlling the status of the energy storage submodule based on the SOC of each energy storage submodule and at least one of the SOH, IGBT junction temperature, and battery temperature, on the one hand, loss balancing can be achieved between each energy storage submodule, avoiding a decrease in the available capacity of the energy storage system due to an imbalance in the SOC or SOH of the energy storage submodules. On the other hand, the battery temperature module can be called in a timely manner to avoid a single energy storage submodule affecting the charge and discharge current of the entire energy storage system, thereby generally improving the utilization and reliability of the energy storage system.

[0009] In one possible implementation, controlling the states of the N energy storage submodules includes: obtaining a weight coefficient of each parameter in the state parameters; and controlling the states of the N energy storage submodules according to the state parameters of each energy storage submodule and the weight coefficient of each parameter in the state parameters.

[0010] In the embodiments of the present application, SOC, SOH, IGBT junction temperature, and battery temperature are all very important for improving system stability and reliability, but their importance varies. Using weight coefficients to reflect the importance of each state parameter to the energy storage system and combining the state parameters with the corresponding weight coefficients to control the state of the energy storage submodules can improve the accuracy of energy storage submodules being switched in and out, further improving the utilization and reliability of the energy storage system.

[0011] In one possible implementation, controlling the states of the N energy storage submodules according to the state parameters of each of the energy storage submodules and the weight coefficient of each parameter in the state parameters includes: determining the quantized value of each parameter in the state parameters according to each parameter in the state parameters; and controlling the states of the N energy storage submodules according to the quantized value and weight coefficient of each parameter in the state parameters.

[0012] In the embodiment of the present application, combining the state parameters and the corresponding weight coefficients to control the state of the energy storage submodule can further improve the utilization and reliability of the system; using specific quantitative values ​​to measure the state parameters of each energy storage submodule is conducive to accurately controlling the state of each energy storage submodule.

[0013] In a possible implementation manner, determining the quantitative value of each parameter in the state parameter includes: when the energy storage system is in charging, determining the SOC quantitative value of each energy storage submodule as Score SOC(x) =100-SOC(x); or when the energy storage system is in discharge, the quantized value of the SOC of each energy storage submodule is determined as Score SOC(x) =SOC(x); where SOC(x) is the SOC of the X-th energy storage submodule; Score SOC(x) is the quantized value of the SOC of the X-th energy storage submodule.

[0014] In the embodiments of the present application, specific quantitative values ​​are used to measure each state parameter of the energy storage submodule, thereby controlling the state of each energy storage submodule, which is beneficial for improving the accuracy of the energy storage system's input and output of energy storage submodules. By assigning different quantitative values ​​to the state parameter SOC in the energy storage system's charging and discharging states, the energy storage system can call different energy storage submodules in the charging and discharging states, achieving SOC balance between each energy storage submodule, avoiding a decrease in the energy storage system's available capacity due to SOC imbalances among the energy storage submodules, and thereby improving system utilization.

[0015] In a possible implementation manner, the determining of the quantitative value of each parameter in the state parameter includes at least one of the following: determining the quantitative value of the SOH of each energy storage submodule as Score SOH(x) =SOH(x); Determine the quantitative value of the IGBT junction temperature of each energy storage submodule as Score temp- IGBT(x) =100-Temp IGBT(x) ; Determine the quantized value of the battery temperature of each energy storage submodule as Score temp- bat(x) =100-Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) Score is the SOH, IGBT junction temperature and minimum battery temperature of the X-th energy storage submodule. SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are the quantitative values ​​of SOH, IGBT junction temperature and minimum battery temperature of the X-th energy storage sub-module.

[0016] In the embodiment of this application, the specific Score SOH(x), Scoretemp-IGBT(x) and Scoretemp-bat(x) are used to measure the state parameters SOH, IGBT junction temperature and minimum battery temperature of the energy storage sub-module, and then the state of each energy storage sub-module is controlled, which is conducive to improving the accuracy of inputting and switching out the energy storage sub-module of the energy storage system.

[0017] In a possible implementation, it is characterized in that controlling the states of the N energy storage sub-modules according to the quantized value and weight coefficient of each parameter in the state parameters includes: determining the comprehensive quantized value P(x) of each energy storage sub-module according to the quantized value and weight coefficient of each parameter in the state parameters of each energy storage sub-module; and according to the P(x) of each energy storage sub-module, selecting the n energy storage sub-modules with the largest P(x) among the N energy storage sub-modules as the put-in state, and the remaining energy storage sub-modules among the N energy storage sub-modules as the cut-out state.

[0018] In this embodiment, during the operation of the energy storage system, the SOC, SOH, IGBT junction temperature, and minimum battery temperature of each energy storage submodule are collected, and these state parameters are normalized. The comprehensive quantized value P(x) is used to evenly sort the energy storage submodules in and out. This control state approach reduces the time complexity of the control algorithm, improves the response efficiency of the energy storage system, and promotes long-term stable operation of the system.

[0019] In a possible implementation, P(x) is:

[0020] P(x)=Weight SOC *Score SOC(x) +Weight health *(Scoretemp-IGBT(x)+Score SOH(x) )+Weight temp-bat *Scoretemp-bat(x);

[0021] Among them, Weight SOC 、Weight health 、Weight temp-bat is the weight coefficient of the SOC, SOH of the energy storage submodule, the IGBT junction temperature, and the lowest battery temperature.

[0022] In the embodiment of the present application, the SOC, SOH, IGBT junction temperature and the minimum battery temperature are normalized, and the energy storage submodules are evenly switched in and out using the comprehensive quantitative value P(x), which reduces the time complexity of the control algorithm, improves the response efficiency of the energy storage system, and is conducive to the long-term stable operation of the system.

[0023] In a possible implementation manner, the sum of the weight coefficients of the state parameters of each energy storage submodule is 1, and the weight coefficient of the SOC is greater than or equal to 0.7.

[0024] In the embodiment of the present application, the weight coefficient can be used to reflect the importance of each state parameter to the energy storage system. Furthermore, the sum of the weight coefficients corresponding to all state parameters of each energy storage submodule is 1, where the weight coefficient corresponding to the SOC is greater than or equal to 0.7. In this way, when controlling the state of the energy storage submodule, the SOC, which plays an important role in the stable control of the energy storage system, can be given priority consideration. This can ensure the long-term stable and reliable operation of the system to the greatest extent.

[0025] In a possible implementation, the method further includes: determining a coefficient of variation of each parameter of each energy storage submodule according to each parameter of each energy storage submodule; and adjusting the weight coefficient according to the coefficient of variation.

[0026] In this embodiment, the state parameters of the energy storage submodules are combined with weight coefficients, and the state of the energy storage submodules is determined by ranking the comprehensive quantized values. This can reduce the time complexity of the control algorithm and improve the system's response efficiency. During system operation, the weight coefficients are dynamically adjusted and the comprehensive quantized values ​​are recalculated, which is conducive to the long-term stable operation of the energy storage system.

[0027] In a possible implementation, adjusting the weight coefficient includes: determining whether the coefficient of variation of each parameter of each energy storage submodule is greater than a coefficient of variation threshold of the system; and adjusting the weight coefficient of the state parameter when the coefficient of variation is greater than the coefficient of variation threshold.

[0028] In the embodiment of the present application, if the coefficient of variation of a state parameter is greater than the coefficient of variation threshold of the energy storage system, the weight coefficient corresponding to the state parameter is changed; otherwise, the weight coefficient corresponding to the state parameter remains unchanged. After judging the coefficient of variation, if the coefficient of variation has changed significantly, the weight coefficient of the corresponding state parameter is changed. This is beneficial to the long-term stable operation of the system and can also improve the efficiency of the energy storage system.

[0029] In a possible implementation, controlling the working status of the N energy storage sub-modules according to the status parameter of each of the energy storage sub-modules includes: controlling the energy storage sub-module to be in a cut-out state when the IGBT junction temperature of the energy storage sub-module is greater than the IGBT junction temperature threshold of the energy storage system.

[0030] In the embodiments of the present application, if the IGBT junction temperature of a particular energy storage submodule exceeds the IGBT junction temperature threshold of the energy storage system, the energy storage submodule will have an adverse impact on the system and should be promptly disconnected from the operation of the energy storage system. By controlling the energy storage submodule whose IGBT junction temperature exceeds the IGBT junction temperature threshold of the energy storage system to be disconnected, the safety of the energy storage system can be maintained.

[0031] In a second aspect, an energy storage system is provided, comprising: N energy storage sub-modules, where N is a positive integer greater than 1; and a controller, configured to obtain status parameters of each of the N energy storage sub-modules, the status parameters including at least one of a battery remaining charge (SOC), a battery health (SOH), an IGBT junction temperature, and a battery temperature; and, based on the status parameters of each energy storage sub-module, controlling the operating states of the N energy storage sub-modules, the operating states including an on-state and a off-state.

[0032] In one possible implementation, the controller is used to: obtain a weight coefficient of each parameter in the state parameters; and control the states of the N energy storage submodules according to the state parameters of each energy storage submodule and the weight coefficient of each parameter in the state parameters.

[0033] In one possible implementation, the controller is used to: determine the quantized value of each of the state parameters based on each of the state parameters; and control the states of the N energy storage submodules based on the quantized value of each of the state parameters and the weight coefficient.

[0034] In a possible implementation manner, the controller is configured to: when the energy storage system is in the process of charging, determine the quantitative value of the SOC of each energy storage submodule as Score SOC(x) =100-SOC(x); or when the energy storage system is in discharge, the quantized value of the SOC of each energy storage submodule is determined as Score SOC(x) =SOC(x); where SOC(x) is the SOC of the X-th energy storage submodule; Score SOC(x) is the quantized value of the SOC of the X-th energy storage submodule.

[0035] In a possible implementation manner, the controller is configured to perform at least one of the following: determining a quantitative value of the SOH of each energy storage submodule as Score SOH(x) =SOH(x); Determine the quantitative value of the IGBT junction temperature of each energy storage submodule as Scoretemp-IGBT(x)=100-Temp IGBT(x); Determine the quantized value of the battery temperature of each energy storage submodule as Scoretemp-bat(x)=100-Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) Score is the SOH, IGBT junction temperature and minimum battery temperature of the X-th energy storage submodule. SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are the quantitative values ​​of SOH, IGBT junction temperature and minimum battery temperature of the X-th energy storage sub-module.

[0036] In one possible implementation, the controller is configured to: determine a comprehensive quantized value P(x) of each energy storage submodule based on the quantized value and weight coefficient of each parameter in the state parameters of each energy storage submodule; and, based on the P(x) of each energy storage submodule, select n energy storage submodules with the largest P(x) among the N energy storage submodules as being in the on-state, and select the remaining energy storage submodules among the N energy storage submodules as being in the off-state.

[0037] In a possible implementation, P(x) is:

[0038] P(x)=Weight SOC *Score SOC(x) +Weight health *(Scoretemp-IGBT(x)+Score SOH(x) )+Weight temp-bat *Scoretemp-bat(x);

[0039] Among them, Weight SOC 、Weight health 、Weight temp-bat is the weight coefficient of the SOC, SOH of the energy storage submodule, the IGBT junction temperature, and the lowest battery temperature.

[0040] In a possible implementation manner, the sum of the weight coefficients of the state parameters of each energy storage submodule is 1, and the weight coefficient of the SOC is greater than or equal to 0.7.

[0041] In a possible implementation, the controller is configured to: determine a coefficient of variation of each parameter of each energy storage submodule according to each of the state parameters of each energy storage submodule; and adjust the weight coefficient according to the coefficient of variation.

[0042] In one possible implementation, the controller is used to: determine whether the coefficient of variation of each parameter of each energy storage submodule is greater than a coefficient of variation threshold of the energy storage system; and adjust the weight coefficient of the state parameter when the coefficient of variation is greater than the coefficient of variation threshold.

[0043] In a possible implementation, the controller is further configured to: control the energy storage submodule to be in a cut-out state when the IGBT junction temperature of the energy storage submodule is greater than an IGBT junction temperature threshold of the energy storage system.

[0044] In a third aspect, a device for controlling an energy storage system is provided, comprising a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call the computer program so that the device implements a method in any possible implementation manner of the first aspect.

[0045] In a fourth aspect, a readable storage medium is provided, wherein the readable storage medium stores a computer program, and when the computer program is executed by a computing device, the computing device implements the method in any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0047] FIG1 is a schematic diagram of an energy storage system used in this application;

[0048] FIG2 is a schematic structural diagram of an energy storage submodule according to an embodiment of the present application;

[0049] FIG3 is a schematic structural diagram of an energy storage submodule according to another embodiment of the present application;

[0050] FIG4 is a schematic flow chart of a control method for an energy storage system according to an embodiment of the present application;

[0051] FIG5 is a schematic flow chart of a control method for an energy storage system according to another embodiment of the present application;

[0052] FIG6 is a schematic block diagram of an energy storage system according to an embodiment of the present application;

[0053] FIG7 is a schematic block diagram of an apparatus for controlling an energy storage system according to an embodiment of the present application. DETAILED DESCRIPTION

[0054] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0056] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0057] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," "attached," and "disposed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0058] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0059] HVDC Flexible is a next-generation DC transmission technology. Its structure consists of converter stations and DC transmission lines (typically DC cables). The converter stations, in turn, are composed of converters, converter transformers, and converter impedance equipment. Unlike current-source converters (HVDCs) based on phase-controlled commutation technology, the converters in HVDC Flexible are voltage-source converters (VSCs). Their key features are the use of turn-off devices and high-frequency modulation. HVDC Flexible offers advantages such as the ability to power passive networks, immunity to commutation failures, the elimination of communication requirements between converter stations, and the ease of configuring multi-terminal DC systems.

[0060] In order to enhance the active power regulation capability of the flexible direct current transmission system and give full play to the role of the flexible direct current transmission system in supporting the power grid, the application of energy storage system in the flexible direct current transmission system has important research significance. The application of energy storage system in the flexible direct current transmission system has the following three main functions: (1) Flexible direct current transmission is an effective way to connect new energy to the grid. By applying energy storage system to flexible direct current transmission system, the adverse effects of the inherent fluctuation of new energy on the power grid can be effectively suppressed; (2) By applying energy storage system to flexible direct current transmission system, the power impact caused by faults on the power grid can be reduced, and the stability and safety of the power system can be improved; (3) Power surplus is an important issue that threatens the safe operation of flexible direct current transmission system. By applying energy storage system to store surplus power, the system fault defense capability can be guaranteed and the operation reliability of flexible direct current transmission system can be improved.

[0061] With the addition of energy storage units to flexible DC transmission systems, maintaining a balanced SOC (State of Charge) (SOC) within these units has become a crucial factor in system stability control. Consequently, research is increasingly underway to achieve SOC balance within flexible DC transmission systems. However, to ensure the long-term stable and reliable operation of energy storage systems, other factors affecting the energy storage units, such as SOH and IGBT switching device losses, must also be minimized.

[0062] In view of this, the embodiments of the present application provide a control method and an energy storage system, which can control the working status of the energy storage submodules in the energy storage system according to multiple states, thereby improving the utilization and reliability of the system.

[0063] Figure 1 is a schematic diagram of the energy storage system used in this application. As shown in Figure 1, the energy storage system 10 includes N energy storage submodules 11, where N is a positive integer greater than 1, and each of the N energy storage submodules 11 can be arranged in series.

[0064] Figure 2 is a schematic diagram of the structure of the energy storage submodule according to one embodiment of the present application, and Figure 3 is a schematic diagram of the structure of the energy storage submodule according to another embodiment of the present application. As shown in Figures 2 and 3, the energy storage submodule consists of a power module 211 and a battery module 212. When the power module 211 in the energy storage submodule is in the on-state, the battery module 212 connected to the power module is in the charging or discharging state; when the power module 211 is in the off-state, the battery module 212 connected to the power module 211 is in the idle state.

[0065] FIG4 is a schematic flow chart of a control method for an energy storage system according to an embodiment of the present application. The energy storage system includes N energy storage submodules, where N is a positive integer greater than 1. For example, the energy storage system may be the energy storage system shown in FIG1 . As shown in FIG4 , the method 400 includes:

[0066] S410, obtaining a state parameter of each of the N energy storage submodules, where the state parameter includes: SOC, and at least one of SOH, IGBT junction temperature, and battery temperature;

[0067] S420 : Control the working states of the N energy storage submodules according to the state parameters of each energy storage submodule.

[0068] The working state includes the switched-on state and the switched-off state.

[0069] In the embodiments of the present application, SOC is the ratio of the battery's capacity after a period of use or long-term storage to its fully charged capacity, usually expressed as a percentage. Its value range is 0 to 1. When SOC = 0, it means the battery is fully discharged, and when SOC = 1, it means the battery is fully charged.

[0070] In the embodiment of the present application, SOH represents the battery capacity, health, and performance status, that is, the percentage of the battery's fully charged capacity relative to the rated capacity. The health of a new battery is 100%, and a completely scrapped battery is 0%.

[0071] In the embodiments of the present application, an IGBT is a fully controlled, voltage-driven, composite power semiconductor device composed of a bipolar junction transistor (BJT) and an insulated gate field-effect transistor (MOS). It combines the advantages of the high input impedance of a metal-oxide-semiconductor field-effect transistor (MOSFET) with the low on-state voltage drop of a giant transistor (GTR). The IGBT junction temperature represents the actual operating temperature of the IGBT and has a certain impact on the stability of the energy storage system.

[0072] In the embodiments of the present application, the battery temperature is the temperature of the battery module in the energy storage submodule during operation, including typical temperatures such as the lowest battery temperature and the highest battery temperature. Because the battery temperature will change during the operation of the energy storage system, the battery temperature value can be collected during the operation of the system, and then cached in the system and updated in real time; or temperature collection conditions can be set in the energy storage system, such as only collecting when the temperature is below a certain value. In short, the present application has no special requirements for the collection method of each state parameter. For the sake of convenience, it is uniformly referred to as obtaining the value of the state parameter.

[0073] On the one hand, N energy storage submodules make up the energy storage system, so the available battery capacity of these N energy storage submodules contributes to the available capacity of the energy storage system. When the SOC difference between energy storage submodules is too large, the system will always prioritize the energy storage submodule with a higher SOC and shelve the energy storage submodule with a lower SOC. Over time, this will cause the available capacity of the energy storage system to decrease, reducing the utilization rate of the energy storage system. In addition, if the system always selects energy storage submodules with high battery health or low battery health, the available capacity of the energy storage system will also decrease.

[0074] On the other hand, if the IGBT junction temperature in the power module of the energy storage submodule is too high, the energy storage submodule will affect the stability of the energy storage system. If the battery temperature in the battery module is too low, the operating current of the energy storage submodule will decrease. If the energy storage submodule is not activated in time, the operating current of the series energy storage system will decrease, affecting the operation of the energy storage system.

[0075] In the above scheme, when the status of the N energy storage submodules in the energy storage system is undetermined, the SOC of each of the N energy storage submodules, as well as at least one of the SOH, IGBT junction temperature, and battery temperature, is first obtained to control the status of each energy storage submodule. This control of the energy storage submodule status based on the SOC and at least one of the SOH, IGBT junction temperature, and battery temperature of each energy storage submodule can, on the one hand, achieve loss balance among each energy storage submodule, avoiding a decrease in the available capacity of the energy storage system due to imbalanced SOC or SOH among the energy storage submodules. On the other hand, it can immediately call upon the module with the lowest temperature, preventing a single submodule from affecting the charge and discharge current of the entire energy storage system, thereby improving the overall utilization and reliability of the energy storage system.

[0076] In some embodiments, a weight coefficient of each parameter in the state parameters is obtained; and the states of the N energy storage submodules are controlled according to the state parameters of each energy storage submodule and the weight coefficient of each parameter in the state parameters.

[0077] To demonstrate the importance of several parameters in the total, different proportional coefficients are assigned to each parameter. In this embodiment, to demonstrate the importance of SOC, SOH, IGBT junction temperature, and battery temperature to the stable operation of the energy storage system, corresponding weight coefficients are assigned to these four state parameters.

[0078] In the above scheme, SOC, SOH, IGBT junction temperature, and battery temperature are all crucial for improving the stability and reliability of the energy storage system, but their importance varies. Using weight coefficients to reflect the importance of each state parameter to the energy storage system and combining them with the corresponding weight coefficients to control the state of the energy storage submodules can improve the accuracy of energy storage submodules being switched in and out, further enhancing the utilization and reliability of the energy storage system.

[0079] In some embodiments, according to each parameter in the state parameters, a quantized value of each parameter in the state parameters is determined; according to the quantized value and weight coefficient of each parameter in the state parameters, the states of the N energy storage submodules are controlled.

[0080] As mentioned above, combining the state parameters and the corresponding weight coefficients to control the state of the energy storage submodule can further improve the utilization and reliability of the system.

[0081] In the above solution, specific quantitative values ​​are used to measure the state parameters of each energy storage submodule, which is conducive to accurately controlling the state of each energy storage submodule.

[0082] In some embodiments, when the energy storage system is in the process of charging, the SOC quantization value of each energy storage submodule is determined as Score SOC(x) =100-SOC(x); or, when the energy storage system is in discharge, determine the quantitative value of the SOC of each energy storage submodule as Score SOC(x) =SOC(x); where SOC(x) is the SOC of the X-th energy storage submodule; Score SOC(x) is the quantized value of the SOC of the Xth energy storage submodule.

[0083] In the embodiment of the present application, the quantized value is to convert the numerical value of the state parameter into a value that can be used for calculation.

[0084] Using specific quantitative values ​​to measure each state parameter of the energy storage submodule, and thus controlling the state of each energy storage submodule, helps improve the accuracy of the energy storage system's entry and exit of energy storage submodules. Regarding the SOC state parameter, when the energy storage system is charging, energy storage submodules with lower SOCs should be prioritized for entry; when the energy storage system is discharging, energy storage submodules with higher SOCs should be prioritized for entry. This ensures SOC balance across all energy storage submodules in the different states of the energy storage system.

[0085] In the above scheme, by assigning different quantitative values ​​to the state parameter SOC in the charging state and discharging state of the energy storage system, the energy storage system calls different energy storage sub-modules in the charging state and discharging state, which can achieve SOC balance between each energy storage sub-module, avoid the reduction of the available capacity of the energy storage system due to SOC imbalance of the energy storage sub-module, and thus improve the utilization rate of the system.

[0086] In some embodiments, the quantitative value of the SOH of each energy storage submodule is determined as Score SOH(x) =SOH(x); Determine the quantitative value of the IGBT junction temperature of each energy storage submodule as Scoretemp-IGBT(x)=100-Temp IGBT(x) ; Determine the quantitative value of the battery temperature of each energy storage submodule as Scoretemp-bat(x)=100-Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) Score is the SOH, IGBT junction temperature and minimum battery temperature of the Xth energy storage submodule. SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are the quantitative values ​​of SOH, IGBT junction temperature and minimum battery temperature of the Xth energy storage sub-module.

[0087] In the embodiment of the present application, the corresponding quantitative values ​​Score of SOH, IGBT junction temperature and battery temperature SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) can be obtained at the same time or at least one of them can be obtained.

[0088] In the above scheme, use the specific Score SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are used to measure the state parameters SOH, IGBT junction temperature and minimum battery temperature of the energy storage sub-module, and then the state of each energy storage sub-module is controlled, which is conducive to improving the accuracy of inputting and switching out the energy storage sub-module of the energy storage system.

[0089] In some embodiments, the comprehensive quantized value P(x) of each energy storage submodule is determined based on the quantized value and weight coefficient of each parameter in the state parameter of each energy storage submodule; based on the P(x) of each energy storage submodule, n energy storage submodules with the largest P(x) among the N energy storage submodules are selected as the input state, and the remaining energy storage submodules among the N energy storage submodules are selected as the cut-out state.

[0090] As mentioned earlier, SOC, SOH, IGBT junction temperature, and battery temperature affect the stability of the energy storage system in different ways, and the importance of these state parameters to the energy storage system varies. Therefore, the quantized values ​​of these state parameters are combined with the corresponding weight coefficients to jointly control the state of the energy storage submodule. However, calculating the value of each state parameter separately during the specific calculation process would be very computationally intensive.

[0091] In this solution, during the operation of the energy storage system, the SOC, SOH, IGBT junction temperature, and minimum battery temperature of each energy storage submodule are collected and normalized. A comprehensive quantitative value, P(x), is used to evenly sequence the switching in and out of the energy storage submodules. This control state approach reduces the time complexity of the control algorithm, improves the response efficiency of the energy storage system, and promotes long-term stable system operation.

[0092] In some embodiments, P(x) is:

[0093] P(x)=Weight SOC *Score SOC(x) +Weight health *(Scoretemp-IGBT(x)+Score SOH(x) )+Weight temp-bat *Scoretemp-bat(x);

[0094] Among them, Weight SOC 、Weight health 、Weight temp-bat It is the weight coefficient of the SOC, SOH of the energy storage submodule, the IGBT junction temperature and the lowest battery temperature.

[0095] In the above scheme, the SOC, SOH, IGBT junction temperature and the minimum battery temperature are normalized, and a specific comprehensive quantitative value P(x) is used to evenly sort the energy storage submodules in and out. This reduces the time complexity of the control algorithm, improves the response efficiency of the energy storage system, and is conducive to the long-term stable operation of the system.

[0096] In some embodiments, the sum of the weight coefficients of the state parameters of each energy storage submodule is 1, and the weight coefficient of SOC is greater than or equal to 0.7.

[0097] State of charge (SOC), state of humidity (SOH), IGBT junction temperature, and battery temperature affect the stability of the energy storage system in different ways. These state parameters also vary in their importance to the system. Therefore, weight coefficients are used to reflect their importance. Furthermore, the sum of the weight coefficients for each energy storage submodule's state parameters is limited to 1. This facilitates calculations and facilitates statistical analysis of changes in the various weight coefficients during the energy storage system's calculations.

[0098] In the above scheme, the weight coefficient can be used to reflect the importance of each state parameter to the energy storage system. Furthermore, the sum of the weight coefficients corresponding to all state parameters of each energy storage submodule is 1, where the weight coefficient corresponding to SOC is greater than or equal to 0.7. In this way, when controlling the state of the energy storage submodule, the SOC, which plays an important role in the stable control of the energy storage system, can be focused on. This can ensure the long-term stable and reliable operation of the system to the greatest extent.

[0099] It should be noted here that the above-mentioned SOC weight coefficient of 0.7 is just an example. The weight coefficient corresponding to SOC can also be 0.6, 0.5 and other values. As long as the weight coefficient corresponding to SOC accounts for the largest proportion in the sum of the weight coefficients corresponding to all state parameters, this application has no special limitation on the specific weight coefficient value of SOC.

[0100] In some embodiments, the coefficient of variation of each parameter of each energy storage submodule is determined based on each parameter of each energy storage submodule; and the weight coefficient is adjusted based on the coefficient of variation.

[0101] In the embodiments of the present application, the coefficient of variation (CV) is the ratio of the standard deviation of the raw data to the mean of the raw data. This ratio can eliminate the effects of the measurement scale and dimension when comparing the degree of dispersion of two sets of data. If the measurement scales of the two sets of data differ greatly, or the data dimensions differ, it is used to eliminate the effects of the measurement scale and dimension. CV is dimensionless, allowing for objective comparison. CV is the absolute value that reflects the degree of dispersion of the data. Its data size is affected not only by the degree of dispersion of the variable values, but also by the average level of the variable values.

[0102] Combining the state parameters of the energy storage submodule with the weight coefficient and using the ranking of the comprehensive quantitative values ​​to determine the state of the energy storage submodule can reduce the time complexity of the control algorithm and improve the system response efficiency.

[0103] In the above scheme, during the operation of the system, the weight coefficient is dynamically adjusted and the comprehensive quantitative value is recalculated, which is conducive to the long-term stable operation of the energy storage system.

[0104] In some embodiments, it is determined whether the coefficient of variation of each parameter of each energy storage submodule is greater than a coefficient of variation threshold of the energy storage system; if the coefficient of variation is greater than the coefficient of variation threshold, the weight coefficient of the state parameter is adjusted.

[0105] During the continuous operation of the energy storage system, the huge amount of calculations may cause the coefficient of variation to change, and this change will directly affect the accuracy of the calculation results. However, if the coefficient of variation changes too little, its impact on the accuracy of the calculation results will be relatively small, so there is no need to change the weight coefficient of the corresponding parameter.

[0106] In the embodiment of the present application, the coefficient of variation threshold of the energy storage system can be manually set at the beginning of the program. The coefficient of variation can be 10 or 20, and this application does not limit this.

[0107] In the embodiment of the present application, if the coefficient of variation of a certain weight coefficient is large, it means that during the operation of the energy storage system, the weight coefficient changes greatly, and therefore it will have a greater impact on the calculation result. Therefore, for state parameters with a large coefficient of variation, the weight coefficient can be adjusted with an increase or decrease range of 0.1. For example, for a smaller weight coefficient, it can be increased by 0.1; for a larger weight coefficient, it can be reduced by 0.1. The above is just an example. The specific adjustment range and adjustment object are mainly based on the actual operation of the energy storage system. For example, for a weight coefficient with a smaller value, the increase or decrease range can be 0.05. This application does not impose any restrictions on this.

[0108] In the above scheme, if the coefficient of variation of a state parameter is greater than the energy storage system's coefficient of variation threshold, the weight coefficient corresponding to that state parameter is changed; otherwise, the weight coefficient corresponding to that state parameter remains unchanged. After judging the coefficient of variation, if there is a significant change in the coefficient of variation, the weight coefficient of the corresponding state parameter is changed. This continuous adjustment of the weight coefficient can make the calculation results more accurate, which is beneficial for the long-term stable operation of the system and improves the efficiency of the energy storage system.

[0109] In some embodiments, when the IGBT junction temperature of the energy storage submodule is greater than the IGBT junction temperature threshold of the energy storage system, the energy storage submodule is controlled to be in a cut-out state.

[0110] If the IGBT junction temperature of a certain energy storage submodule is greater than the IGBT junction temperature threshold of the energy storage system, then the energy storage submodule will have an adverse effect on the system, so it should be cut off from the operation of the energy storage system in time.

[0111] In the above solution, the safety of the energy storage system can be maintained by controlling the energy storage submodule whose IGBT junction temperature is greater than the IGBT junction temperature threshold of the energy storage system to be cut out.

[0112] In the embodiment of the present application, the control method of the energy storage system can be set to start when the energy storage sub-module to be put into use changes, or it can be set to start at a fixed period. The present application does not impose any restrictions on the starting conditions of the control method.

[0113] 5 is a flow chart of a control method for an energy storage system according to another embodiment of the present application. Similar steps in this embodiment to those in the previous embodiment can be referred to the previous embodiment and will not be described again for the sake of brevity.

[0114] Step S501, start.

[0115] Step S502: Determine the number n of energy storage submodules that need to be put into operation.

[0116] Step S503, obtaining SOC, SOH, IGBT junction temperature and battery temperature.

[0117] Step S504, obtain the weight coefficient of each state parameter: Weight SOC 、Weight health 、Weight temp-bat .

[0118] Step S505, determine Temp IGBT(x) Is it greater than the IGBT junction temperature threshold MAX? temp-IGBT(x) .

[0119] Step S506: If Temp IGBT(x) Greater than MAX temp-IGBT(x) , the energy storage submodule is in the cut-out state.

[0120] Step S507: If Temp IGBT(x) Not greater than MAX temp-IGBT(x) , get cache Temp bat(x) .

[0121] Step S508 , determining the quantitative values ​​of SOC, SOH, IGBT junction temperature and battery minimum temperature.

[0122] Step S509: Calculate the comprehensive quantitative value P(x) of each energy storage submodule.

[0123] Step S510, sorting according to P(x).

[0124] Step S511: determine that the first n energy storage submodules of P(x) are in the on-state.

[0125] Step S512: Count the coefficients of variation of all energy storage submodules.

[0126] Step S513: determine whether the coefficient of variation is greater than the coefficient of variation of the energy storage system.

[0127] Step S514: If the coefficient of variation is greater than the coefficient of variation of the energy storage system, adjust the weight coefficients to keep the sum of the weight coefficients equal to 1, and Weight SOC >0.7.

[0128] Step S515: If the coefficient of variation is not greater than the coefficient of variation of the energy storage system, determine whether the system should exit.

[0129] Step S516: If exiting the system, end.

[0130] The present application also provides an energy storage system. FIG6 is a schematic block diagram of an energy storage system according to an embodiment of the present application. As shown in FIG6 , the energy storage system 10 includes: N energy storage submodules 11, where N is a positive integer greater than 1; and a controller 12 for obtaining state parameters of each of the N energy storage submodules 11, the state parameters including at least one of the remaining battery charge (SOC), the battery health (SOH), the IGBT junction temperature, and the battery temperature. Based on the state parameters of each energy storage submodule, the controller 12 controls the operating state of the N energy storage submodules 11, including an on-state and a off-state.

[0131] In some embodiments, the controller 12 is configured to: obtain a weight coefficient of each state parameter; and control the states of the N energy storage submodules according to the state parameter of each energy storage submodule and the weight coefficient of each state parameter.

[0132] In some embodiments, the controller 12 is used to: determine the quantized value of each of the state parameters according to each of the state parameters; and control the states of the N energy storage submodules according to the quantized value and weight coefficient of each of the state parameters.

[0133] In some embodiments, the controller 12 is used to: when the energy storage system is in the charging state, determine the quantitative value of the SOC of each energy storage submodule as Score SOC(x) =100-SOC(x); or when the energy storage system is in discharge, the quantitative value of the SOC of each energy storage submodule is determined as Score SOC(x) =SOC(x); where SOC(x) is the SOC of the X-th energy storage submodule; Score SOC(x) is the quantized value of the SOC of the Xth energy storage submodule.

[0134] In some embodiments, the controller 12 is configured to perform at least one of the following: determining a quantitative value of the SOH of each energy storage submodule as Score SOH(x) =SOH(x); Determine the quantitative value of the IGBT junction temperature of each energy storage submodule as Scoretemp-IGBT(x)=100-Temp IGBT(x); Determine the quantized value of the battery temperature of each energy storage submodule as Score temp- bat(x) =100-Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) Score is the SOH, IGBT junction temperature and minimum battery temperature of the Xth energy storage submodule. SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are the quantitative values ​​of SOH, IGBT junction temperature and minimum battery temperature of the Xth energy storage sub-module.

[0135] In some embodiments, the controller 12 is used to: determine the comprehensive quantized value P(x) of each energy storage submodule based on the quantized value and weight coefficient of each parameter in the state parameters of each energy storage submodule; based on the P(x) of each energy storage submodule, select n energy storage submodules with the largest P(x) among N energy storage submodules as the input state, and the remaining energy storage submodules among the N energy storage submodules as the cut-out state.

[0136] In some embodiments, P(x) is:

[0137] P(x)=Weight SOC *Score SOC(x) +Weight health *(Scoretemp-IGBT(x)+Score SOH(x) )+Weight temp-bat *Scoretemp-bat(x);

[0138] Among them, Weight SOC 、Weight health 、Weight temp-bat It is the weight coefficient of the SOC, SOH of the energy storage submodule, the IGBT junction temperature and the lowest battery temperature.

[0139] In some embodiments, the sum of the weight coefficients of the state parameters of each energy storage submodule is 1, and the weight coefficient of SOC is greater than or equal to 0.7.

[0140] In some embodiments, the controller 12 is configured to: determine the coefficient of variation of each parameter of each energy storage submodule according to each parameter in the state parameters of each energy storage submodule; and adjust the weight coefficient according to the coefficient of variation.

[0141] In some embodiments, the controller 12 is configured to determine whether the coefficient of variation of each parameter of each energy storage submodule is greater than a coefficient of variation threshold of the energy storage system; and adjust the weight coefficient of the state parameter if the coefficient of variation is greater than the coefficient of variation threshold.

[0142] In some embodiments, the controller 12 is configured to control the energy storage submodule to be in a cut-out state when the IGBT junction temperature of the energy storage submodule is greater than an IGBT junction temperature threshold of the energy storage system.

[0143] The present application also provides an energy storage system control device. As shown in FIG7 , the energy storage system control device 70 includes a processor 71 and a memory 72 . The memory 72 is used to store computer programs, and the processor 71 is used to call the computer programs, so that the device 70 implements the methods of the various embodiments of the present application.

[0144] The embodiments of the present application further provide a readable storage medium storing a computer program that, when executed by a computing device, enables the computing device to implement the methods of various embodiments of the present application.

[0145] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A control method for an energy storage system, characterized in that, The energy storage system includes N energy storage sub-modules, where N is a positive integer greater than 1. The method includes: Obtaining the state parameters of each of the N energy storage sub-modules, where the state parameters include: the remaining battery charge SOC, and at least one of the battery health SOH, the IGBT junction temperature, and the battery temperature; Controlling the working states of the N energy storage sub-modules according to the state parameters of each of the energy storage sub-modules, where the working states include the input state and the cut-out state.

2. The control method according to claim 1, characterized in that Controlling the states of the N energy storage sub-modules includes: Obtaining the weight coefficient of each parameter in the state parameters; Controlling the states of the N energy storage sub-modules according to the state parameters of each of the energy storage sub-modules and the weight coefficient of each parameter in the state parameters.

3. The control method according to claim 2, characterized in that Controlling the states of the N energy storage sub-modules according to the state parameters of each of the energy storage sub-modules and the weight coefficient of each parameter in the state parameters includes: Determining the quantization value of each parameter in the state parameters according to each parameter in the state parameters; Controlling the states of the N energy storage sub-modules according to the quantization value and the weight coefficient of each parameter in the state parameters.

4. The control method according to claim 3, characterized in that, Determining the quantization value of each parameter in the state parameters includes: When the energy storage system is in the charging state, determine that the quantization value of the SOC of each energy storage sub-module is Score SOC(x) = 100 - SOC(x); or When the energy storage system is discharging, determine that the quantization value of the SOC of each energy storage sub-module is Score SOC(x) = SOC(x); Among them, SOC(x) is the SOC of the Xth energy storage sub-module; Score SOC(x) is the quantization value of the SOC of the Xth energy storage sub-module.

5. The control method according to claim 3 or 4, characterized in that, Determining the quantization value of each parameter in the state parameters includes at least one of the following: Determine that the quantization value of the SOH of each of the energy storage sub-modules is Score SOH(x) = SOH(x); Determine that the quantization value of the IGBT junction temperature of each of the energy storage sub-modules is Scoretemp-IGBT(x) = 100 - Temp IGBT(x) ; Determine that the quantization value of the battery temperature of each energy storage sub-module is Scoretemp-bat(x) = 100 - Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) are the SOH, IGBT junction temperature, and the lowest battery temperature of the Xth energy storage sub-module, Score SOH(x) , Scoretemp-IGBT(x), and Scoretemp-bat(x) are the quantization values of the SOH, IGBT junction temperature, and the lowest battery temperature of the Xth energy storage sub-module.

6. The control method according to claim 4 or 5, characterized in that, Controlling the states of the N energy storage sub-modules according to the quantization value and the weight coefficient of each parameter in the state parameters includes: Determining the comprehensive quantization value P(x) of each energy storage sub-module according to the quantization value and the weight coefficient of each parameter in the state parameters of each energy storage sub-module; Selecting the n energy storage sub-modules with the largest P(x) among the N energy storage sub-modules as the input state, and the remaining energy storage sub-modules among the N energy storage sub-modules as the cut-out state according to the P(x) of each energy storage sub-module.

7. The control method according to claim 6, wherein The P(x) is: P(x) = Weight SOC * Score SOC(x) + Weight health *(Scoretemp - IGBT(x)+ Score SOH(x) )+ Weight temp-bat * Scoretemp - bat(x); Among them, Weight SOC , Weight health , Weight temp-bat are the weight coefficients of the SOC, SOH, IGBT junction temperature and the lowest battery temperature of the energy storage sub-module.

8. The control method according to any one of claims 1 to 7, characterized in that The sum of the weight coefficients of the state parameters of each energy storage sub-module is 1, and the weight coefficient of the SOC is greater than or equal to 0.

7.

9. The control method according to any one of claims 1 to 8, characterized in that, The method further includes: Determining the coefficient of variation of each parameter of each energy storage sub-module according to each parameter in the state parameters of each energy storage sub-module; Adjusting the weight coefficient according to the coefficient of variation.

10. The control method according to claim 9, wherein Adjusting the weight coefficient includes: Judging whether the coefficient of variation of each parameter of each energy storage sub-module is greater than the coefficient of variation threshold of the energy storage system; Adjusting the weight coefficient of the state parameters when the coefficient of variation is greater than the coefficient of variation threshold.

11. The control method according to any one of claims 1 to 10, characterized in that, Controlling the working states of the N energy storage sub-modules according to the state parameters of each of the energy storage sub-modules includes: Controlling the energy storage sub-module to be in the cut-out state when the IGBT junction temperature of the energy storage sub-module is greater than the IGBT junction temperature threshold of the energy storage system.

12. An energy storage system, characterized in that, Includes: N energy storage sub-modules, where N is a positive integer greater than 1; A controller is configured to obtain state parameters of each of the N energy storage sub - modules. The state parameters include: state of charge (SOC) of the battery, state of health (SOH) of the battery, at least one of IGBT junction temperature and battery temperature. According to the state parameters of each energy storage sub - module, the controller controls the working states of the N energy storage sub - modules. The working states include an input state and a cut - out state.

13. The energy storage system according to claim 12, wherein The controller is configured to: Obtain the weight coefficient of each parameter in the state parameters; Control the states of the N energy storage sub - modules according to the state parameters of each energy storage sub - module and the weight coefficient of each parameter in the state parameters.

14. The energy storage system according to claim 13, characterized in that, The controller is configured to: Determine the quantization value of each parameter in the state parameters according to each parameter in the state parameters; Control the states of the N energy storage sub - modules according to the quantization value of each parameter in the state parameters and the weight coefficient.

15. The energy storage system according to claim 14, wherein The controller is configured to: When the energy storage system is in the charging state, determine that the quantization value of the SOC of each energy storage sub-module is Score SOC(x) = 100 - SOC(x); or When the energy storage system is discharging, the quantified value of the SOC of each energy storage sub-module is determined as Score SOC(x) = SOC(x); Among them, SOC(x) is the SOC of the Xth energy storage sub-module; Score SOC(x) is the quantization value of the SOC of the Xth energy storage sub-module.

16. The energy storage system according to claim 14 or 15, characterized in that, The controller is configured to perform at least one of the following: Determine that the quantization value of the SOH of each of the energy storage sub-modules is Score SOH(x) = SOH(x); Determine that the quantization value of the IGBT junction temperature of each of the energy storage sub-modules is Scoretemp-IGBT(x) = 100 - Temp IGBT(x) ; Determine that the quantization value of the battery temperature of each energy storage sub-module is Scoretemp-bat(x) = 100 - Temp bat(x) ; Among them, SOH(x), Temp IGBT(x) and Temp bat(x) are the SOH, IGBT junction temperature and the lowest battery temperature of the Xth energy storage sub-module, Score SOH(x) , Scoretemp-IGBT(x) and Scoretemp-bat(x) are the quantization values of the SOH, IGBT junction temperature and the lowest battery temperature of the Xth energy storage sub-module.

17. The energy storage system according to claim 15 or 16, characterized in that, The controller is configured to: Determine the comprehensive quantization value P(x) of each energy storage sub - module according to the quantization value and weight coefficient of each parameter in the state parameters of each energy storage sub - module; According to P(x) of each energy storage sub - module, select n energy storage sub - modules with the largest P(x) among the N energy storage sub - modules to be in the input state, and the remaining energy storage sub - modules among the N energy storage sub - modules to be in the cut - out state.

18. The energy storage system according to claim 17, characterized in that, The P(x) is: P(x) = Weight SOC *Score SOC(x) +Weight health *(Scoretemp - IGBT(x) + Score SOH(x) ) + Weight temp-bat *Scoretemp - bat(x); Among them, Weight SOC , Weight health , Weight temp-bat are the weight coefficients of the SOC, SOH, IGBT junction temperature and the lowest battery temperature of the energy storage sub-module.

19. The energy storage system according to any one of claims 12 to 18, wherein The sum of the weight coefficients of the state parameters of each energy storage sub - module is 1, and the weight coefficient of the SOC is greater than or equal to 0.

7.

20. The energy storage system according to any one of claims 12 to 19, characterized in that, The controller is configured to: Determine the coefficient of variation of each parameter of each energy storage sub - module according to each parameter in the state parameters of each energy storage sub - module; Adjust the weight coefficient according to the coefficient of variation.

21. The energy storage system according to claim 20, wherein The controller is configured to: Judge whether the coefficient of variation of each parameter of each energy storage sub - module is greater than the coefficient of variation threshold of the energy storage system; In the case where the coefficient of variation is greater than the coefficient of variation threshold, adjust the weight coefficient of the state parameters.

22. The energy storage system according to any one of claims 12 to 21, characterized in that, The controller is further configured to: In the case where the IGBT junction temperature of the energy storage sub - module is greater than the IGBT junction temperature threshold of the energy storage system, control the energy storage sub - module to be in the cut - out state.

23. A device for controlling an energy storage system, characterized in that, It includes a processor and a memory. The memory is used to store a computer program, and the processor is used to call the computer program to enable the device to implement the method according to any one of claims 1 to 11 above.

24. A readable storage medium, characterized in that, The readable storage medium stores a computer program, and when the computer program is executed by a computing device, the computing device is enabled to implement the method according to any one of claims 1 to 11 above.

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